Measured-service telephone system.



J. ERICKSON.

MEASURED SERVICE TELEPHONE SYSTEM.

APPLICATION FILED AUG.5, I910.

Patented May 8, 1917.

4 SHEETS-SHEET I.

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J. ERICKSON.

MEASURED SERVICE TELEPHONE SYSTEM.

APPLICATION FILED AUG.5, 1910.

LQQQfiGSO Patenfed May 8,1917.

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J. ERICKSON.

MEASURED SERVICE TELEPHONE SYSTEM.

APPLICATION FILED Aue.s. 1910.

EL QQ5 6QSQ Patented May 8,1917.

4 SHEETS-SHEET 3.

J. ERICKSON.

MEASURED SERVICE TELEPHONE SYSTEM.

APPLICATION FILED Aue.5. I910.

Patenfied May 8, 1917.

4 'SHEETSSHEET 4.

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some mrcxson, or cmcaeo, armors, assrenoa 'ro aurone'rrc ELECTRIC comrm,or cmcas nrmors, A eonrom'rron or rumors.

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messes.

have invented a certain new and useful Tm provement in Measured ServiceTelephone Systems, of which the following is a speckfication. v

My invention relates to telephone systems in general, but moreparticularly to automatic or semi-automatic telephone systems,

and especially to measured service systems. The principal object of myinvention is to provide a novel and efficient measured servicearrangement for two-wire systems, and by this is meant a system in whichthe two sides of the calling line are controlled in series to operateand release the switches at the exchange or central station, as willhereinafter more fully appear.

In the accompanying drawings Figures 1 and 2 represent a completeconnection between a calling substation A (Fig. 1) and a calledsubstationA (Fig. 2) in a system embodying'the principles of myinvention. In Fig. 1 there is represented an automatic substation A tothe line conductors of which there is allotted at the central office anindividual or line switch C. At D there is shown a master switch forcontrolling a group of line switches C. The line switches of this grouphave common access to a number of trunk lines which lead to firstselector switches. E. A number of first selectors have common access toa number of second selectors F, which in turn have access to connectorswitches H (Fig. 2) by means of which connection, may be completed withsubscribers linesi' Fig. 3 is a diagrammatic View of a portion of thecentral oflice apparatus, showing the essential features of the masterswitch D (Fig. 1). t

Fig. 4 is a front elevation of my improved substation coinecollectingdevice.

Fig. 5 is a side elevation of the apparatus shown in Fig. 4.

v Fig. 6 is a partial sectional view on the line 6-6 of Fig. t.

Figs. 7 and 8 are views of portions of the coin-collecting device indifierent operated positions.

As thus illustrated, the construction and method of operation of thecoin-collecting dev ce i a fellows In F gs t and 5 a f Specification ofLetters Patent.

snnvrcn TELEPHONE srsrisra.

Patented May 8, 1911?.

Application filed August 5, 1910. Serial No. 575,751.

is shown to the front surface of plate 2 Also,

which there is attached a coin chute 3.

I to the front of the plate 3. but insulated therefrom and from eachother. there is mounted a. group of contact springs i. 5 and 6. Thelower end of the spring i carries a swingingarm 7. Back of the plate '2there is mounted a polarized electromagnet comprising a permanent magnet8 and two coils 9 and 10. The armature 11 of the electromagnet isprovided with a downwardly-projecting arm 12. The lower end of the arm12- is bent forward above the arm 7. 'hen the armature 11- is tippeddownward to the right. the end of the arm 12 engages a small lug 13 onthe top of the arm 7 and carries saidarm to the left. \Vhen the arm T isthus moved to the left its left endprojects into an opening 1% in theside of the coin chute. while the spring i is. forced into engagementwith the springs?) and 6. If a coin is dropped down the chute while thearm 7 is in this position, the coin will strike the end of said arm.carrying the lug 13 out of engagement with the arm 12. whereby thesprings l. 5 and 6 are permitted to separate. Fig. showsthe position ofthe. apparatus just before the coin strikes the arm 7. Fig. 8 shows theapparatus after the arm 7 has been disengaged from the arm 12- by thecoin. The spring 15 serves to hold the arm 7 in engagement with the arm12 until the coin is deposited. After the arm '1' has been released itcannot be drawn over again until the electromagnet has been energized inthe reverse direction to bring the arm 12 behind the lug'13 again.

The armature of the electronmgnet is pivoted to the bracket 16. which isclamped between two pairs of nuts 12' and 18 on screws 19 which projectfrom the top of the side brackets 20. With this method of mounting thearmature is easily adjustable toward or away from the poles of themagnet.

Mounted in the front wall of the coin chute is agate 21 the lower end ofwhich is forced against the back wa l of the chute by the spring 22, asshown in Fig. 6. Then a coin is dropped in the chute it forces the gateout and passes on with but little obstruction. If, however. a wire oranything of a similar nature should be inserted in the chute for thepurpose of fraudulently operatingthe arm i'. the gate "21 acts as aclutch and seizes the wire when an attempt is made made with the coindevice by means of bind ing posts in the block 23.

1 spring (not shown) The automatic substations may be of. any suitableor approved type. Those in connection with-which I have elected toillustrate my invention, as shown at A in Fig. 1, comprise the usualreceiver 25, switch hook 26, transmitter 21, induction coil 28, ringer29 and condenser 30. In addition the substation A is provided with theimpulse springs 31 and 32 and an impulse wheel 33. The impulse wheel 33carries upon its periphery the impulse teeth 34 and is secured to ashaft 35 to which there is also attached a dial (not shown) providedwith finger holes, through the medium of which the impulse wheel may berotated. As the impulse wheel is returned to normal position by a afterit has been rotated for any digit, each of the teeth 34 which pass theend of spring 31 forces said spring out of engagement with spring 32.The number of times these springs are separated depends upon the digitcalled. Connected to the line of substation A there is also shown one ofmy improved coin-collecting devices. The coin-collectingdiagrammatically in Fig. 1 and the parts are designated by the samereference numerals as in Figs. 4 and 5.

The line switch C, which is individual to the line of substation A, andthe master switch D are modified forms of the general type of lineswitch and master switch disclosed, in British Patent #26,301 of 1906,

and in theAmerican Telephone Journal of New York, N. Y., of June 6,1908.As herein represented, the line switch C comprises, among other details,a plunger 38 (Fig. 3) attached to the end of a so-called plunger arm 39which is controlled by the magnet 40. The magnet 40 also controls therelay armatures 41 and 42 and is composed of four windings, namely, apull-in winding 43, a holding or cut-01f winding 44, line wind' g 46 andan auxiliary winding 45. The core of the magnet is provided near thecenter of its length with a lateral projection 47 by means of which themagnet is mounted upon the bracket 48, upon which latter the armatures39, 41 and 42 are pivoted. With this method of mounting the magnet, themagnetic circuit of the windings 43 and 44 is maintained separate fromthat of the windings 45 and 46, so that the armatures at one end of themagnet are not affected by the energization of the windings upon theother end. Of the two windmgs upon the upper end of the magnet, only thewinding 43 is strong enough to attract the plunger arm 39 from itsnormal position. The winding 44 is not strong enough to thus operate theplunger arm,but will hold it in an operated position after it has beendrawn device is represented only.

down by the winding 43. When the hager arm 39 is attracted by the magnet40 the I plunger of the switch is forced into a bank the line switchesof the group which is controlled by the) master switch D. The plungersof the line switches of this group normally engage the plunger shaft 57(Fig. 3) and, through the medium of the master switch D, are normallymaintained opposite the terminal of an idle trunk line. The masterswitch consists essentially of a motor magnet 58 for rotating theratchet wheel 59. The ratchet wheel 59 is connected with the shaft 60 bymeans of a link 61' in such a mamier that a rotary motion of the ratchetwheel is transmitted to the plunger shaft 57', imparting to it anoscillating mot-ion about the shaft 60, so as to move the idle plungersback and forth in front of their-trunk terminals. To the shaft 60 thereis secured a locking plate 62 provided near its outer edge with a numberof openings 63 which 111g a common segment 65 and one indi-' vidualsegment a for each trunk to which the line switches have access. Thewiper 66 always keeps the common segment in electrical connection withthe individual segment corresponding to the trunk line heforewhich theidle plungers are being held by the master switcl The selector E is ofthe general type of selector disclosed in United States Letters Patent#815,321, granted to Keith, Erickson and Erickson, March 13, 1906, beingsomewhat modified, however, so as to operate in a two-wire system, i.e., a system in which the central oflice apparatus is controlled fromthe calling substation over the two sidesof the] line in series.represented, the selector E comprises the usual wipers 6T, 68 and 69carriedupona vertically and rotatably movable shaft (not shown) which iscontrolled by the vertical magnet 70 and rotary magnet 71. The usualside switch, compris ng the wipers 72, '4' 3,

74 and 75, is controlled by the private magnet 'i 6 in a well knownmanner. The opera- As herein.

ing subscriber through the double-wound line relay 7 7. Means forrestoring the mechanism of the selector to normal position is providedin the release magnet 78, which is connected with the battery only whenthe switch shaft is raised one or more steps, whereby the arm- 79,

which is carried by said shaft, permits the spring 81 to engage spring80. The mechanism of the selector E is released immediately upon theenergization of the release magnet rather than by its denergization, asshown in the saidselector patent. The relays 82, 83 and 84 are slowacting relays,- i. e., they are slow to dee-nergize after theirenergizing circuits have been broken. This slow action is usuallyaccomplished by s'ecuring a heavy ring of-copper around one end of thecore of the relay. The selector F is similar to the selector E with theaddition of side switch wiper 85.

The-connector H is of the general type of connector switch disclosed inUnited States Letters Patent #815,176, granted March 13, 1906, to Keith,Erickson and Erickson, but, like the selectors, is modified in order tooperate in a two-wire system. Like the selectors, the connector isprovided with a shaft (not shown) carrying the-wipers 86,

87 and 88, and is controlled by the vertical magnet 89 and rotary magnet90. The usual "side switch is controlled by the private magnet 91 in theusual manner. The line relay 92 is connected with the line conductorsthrough the springs of a reversing relay 93. The connector is providedwith a so-called back bridge relay called substation is provided withtalking battery current, and with a ringer relay through the medium ofwhich ringing current may be applied to the called line after connectionis completed therewith.

The substation A'and line switch C are similar to the substation A andline switch C, respectively. At M there is shown a ringing currentgenerator and at L is shown a busy signalingmachine comprisin a currentinterrupter 93 and an induction coil 94*. For operating the centraloffice appa-.

ratus and for furnishing talking current there is provided a battery Bhaving one pole (preferably the positive) grounded at G.

Having given a general description of the apparatus, 1 will now explainin detail the operations by which one subscriber establishes connectionwith another in a system embodying the principles of my invention, Itwill be explained how substation A may obtain connection with substationA, the number of which is assumed to be 2220. hen the callingsubscriberremoves his receiver preparatory to making a call the switch hook rises,permitting the spring 95 177 through which thethrough broken, and abridge consisting of the substation transmitter, primary winding of theinduction coil and the windings of the coincollecting device is closedacross the line conductors 98 and 99. The closure of this bridge acrossthe line completes an energizing circuit through the line winding 46 ofthe switch C. This ground G through springs 101 and 102, line 99,springs 95 and 96, induction coil 28, impulse springs 31 and 32, coils10'and 9 of the coin-collecting device, line 98, springs 104 and 103 andwinding 46 to battery lead 100. The current through the coils of thecoin-collecting device at this time flows in such a direction as toattract the armature toward coil 10, as shown in Fig. 1, therebybringing the end of arm 12 into engagement with the lug 13 on the arm 7.The energization of the winding 46 serves to attract the armature 42,which operates to force the spring 105 into engagement with spring 101,whereby a circuit is closed through the pull-in winding 43. This circuitextends from ground GK through springs 101 and 105, windings 43 and 45,contact point 107 and armature to battery lead 100. gizing, attracts thearmature 41 and plunger arm 39. The armature 41, upon being attracted,operates to disconnect the line winding 46 and ground G from the callingline. The armature 42 does not fall back imme diately upon thedenergization of the winding 46, but remains held up by current fiowingin the winding 45 until the plunger arm I 39 forces spring 108 intocontact with spring 109, whereby cuited and consequently denergizesslowly to hold the armature 42 in its operated position for an instantlonger. Before the armature 42 is restored sufliciently to break thecircuit of winding 43 a circuit is closed the winding 44 in thefollowing manner: When forced into contact with springs 50 and 56,respectively, by the plunger 0 switch C a circuit is closed through theline relay 1'7 of the selector E. This circuit extends from ground Gthrough lower winding of relay 77, side switch wiper 7 3, springs 56 and55, thence over the heavy conductors to and throu h substation A-andback over the other side of the line through upper winding of relay 7 7to the-battery' holding winding 44 of the line switch C, said circuitextends from f the line primary winding of The winding 43, upon ener- Ithe winding 45 is short-cir- 4 the springs 49 and 55 are i circuitextending from ground G V 1 circuit extending from springs 113 and 114,52 and 51 and winding H to battery lead 100. The current in this windingserves to hold the plunger arm 39 and armature 41 in their operatedpositions after the winding *3 has been de'e'nergized. The energizationof the relay 82 at the selector E also extends a guarding potential fromground G over conductor 115 to the c011- nector private bank contacts ofthe calling line.

'hen the springs 53 and 54 are forced into a contact by the plunger ofthe line switch. a circuit is closed through the master switch relay116. This circuit extends from ground G through springs 53 and 51.contact point 117. wiper 66. segment and relay 116 to batterylead 100.The relay 116. upon energizing. operates to close a circuit through therelay 66. The relay 66. upon energizing, operates to withdraw the pin 64from the plate 62 and to close the "circuit of the motor magnet 58. Thiscircuit extends from ground G 'through magnet 58. interrupter springs118. contact point 119 and armature 65 to battery lead 100. As long asthe armature 65 engages contact point 119. the magnet 58 operates in amanner similar to that of a buzzer to rotate the ratchet wheel 59 stepby step to advance the idle line switch plungers away from the trunkjust seized. After the plungers have been advanced a short distance, thewiper 66 passes off the contact point 117 and allows the relays 116 and66' to deenergize. The armature 65 does not fall back immediately uponthe deenergization of relay 66.'but remains in contact with contact.point 119 until the next'opening in the plate 62 passes under the pin64. When the next opening does pass under the pin 64 the armature 65falls back. forcing the pin into this opening to lock the plunger shaftand breaking the circuitof the motor magnet 58. The foregoing is theoperation of the master switch in case the next trunk line after-the oneseized by the switch C is idle. If. however. this next trunk is busy,the wiper 66 finds the corresponding contact in themaster switch bankgrounded, and consequently the relays 116 and 66 remain energized whilethe next opening is passing under the pin Gtand the plungers are carriedpast the busy trimk to an idle one. As long as the master switch isoperating, the armature 65 is disengaged from the spring 107 and spring107 engages spring 120, whereby the pull-in windings of all the idleline switches are disconnected from the ba tery and connected to thebusy signaling machine L. With this arrangement no line switch can beoperated while its plunger is being moved from one trunk to another, andany subscriber who attempts to make a call at that time will receive theground G through busy signal. due. to the inductive'relation between theline winding 16 and the winding 15. which is then connected to the busysignaling machine L. y

The foregoing are the operations which take place immediately upon theremoval of the receiver at the calling substation. The callingsubscriber now operates his calling dial in the usual manner for thefirst digit '2 of the desired number. As the impulse wheel'33 returns tonormal position after being rotated for this digit, the impulse springs31 and 32- are separated twice momentarily. Each time the springs 31 and32 are separated, the energizing circuit of the line relay 7? of theselector E is broken, allowing said relay to be momentarily deenergized.Since the relay S2 of the selector is slow acting. it does not have timeto deenergize during the momentary interruption of its circuitatthesprings 111 and Consequently, the engagement of springs 110 and 112closes an energizing circuit through the vertical magnet 70. Thiscircuit extends from ground G through springs 110 and 112. springs 121and 122. private magnet relay 83. vertical magnet 70 and the side switchwiper Ti to battery lead 100. Since the digit called is 2,.the verticalmagnet receives two impulses over this circuit and operates to raise theswitch shaft and wipers two steps to a'position opposite the'second rowor level of bank contacts. The private magnet relay 83 which is includedin the energizing circuit of the vertical magnet is energized with thefirst impulse, but being a slow acting relay does not have time todeenergize until the last impulse for the digit is transmitted. In itsenergized condition the relay 83 operates to close a circuit extendingfrom ground G through springs 124 and 125 and private magnet '4' 6 tobattery lead 100. 'hen the relay 83 deenergizes, after the last impulseis transmitted to the vertical magnet, this circuit through the privatemagnet is broken. The private magnet thereupon deenergizes and allowsthe side switch to pass to second position. The movement of the sideswitch wiper 74 from first to second position disconnects the batteryfrom the vertical magnet 70 and completes an energizing circuit throughthe rotary magnet 71. This circuit extends from ground G: through theinterrupter springs 19 0, rotary magnet 71, relay 8% and side switch 74to battery lead 100. Upon the closure of this circuit the rotary magnetattracts its armature, which operates to rotate the shaft wipers onestep, to press down the armature of the private magnet 7 6 and to openthe circuit of its own magnet at the interrupter springs 120. TVhen thecircuit of the rotary magnet is thus opened, its armature falls backand, if the first trunk line upon which the wipers in use,

the private magnet armature also falls and permits the side switch topass to third position. If. however, the firsttrtmk line of the secondlevel is already busy, the private wiper GS finds the first contactwhich it engages providedwith a guarding ground potential. When thewiper GS-thus engages the grounded contact, the locking circuit iscompleted through the side switch wiper T5 tin second position) and theprivate magnet To to battery lead 100. The private magnet thus becomesenergized and locks the side switch in second position. As long as theside switch remains thus locked, the rotary magnet continues to operatein a mamier similar to that of a buzzer to rotate the selector wipersstep by step until an idle trunk line is found. When the private wiper65 engages the non-grounded contact of an idle trunk, the private magnet76 tie-- energizes and permits the side switch to pass to thirdposition, thereby breaking the circuit of the rotary magnet. Themovement of the side switch wipers 72 and 73 from second to thirdposition disconnects the line relay 7? from the line and extends.

the line connection through the shaft wipers GT and 69- to the secondselector F. The line relay 12? in the selector F then becomes energizcdin the same manner in which the relay T7 of the selector E was energizedwhen the connection was first extended through that selector. Theenergization of the relay 12? serves to close an energizing circuitthrough the slow acting relay 128 in the same mamier in which thecircuit of relay S2 was closed by the relay 77. The relay 12S. uponenergizing, extends the guarding potential from ground G to side switchwiper S5 and spring 12 and 130 and to the private bank contacts of theseized trunk in the banks of all of the selectors E which have access tothis trunk. A circuitalso extends from the ground G through the saidselector private bank contacts, private wiper 68. side switch wiper T5,springs 1 31 and 132 and relay S2 to battery lead 100. This circuitprevents the relay 82 from deenergizing after its former circuit isbroken by the deenergization of the relay 77 when the side switch oftheselector E pas es to third position. A short period of time elapsesbetween the time when the side switch of the selector E passes to thirdposition and the time when the relay 12S energizes to extend a guardingpotential back to the first selector private bank contacts from theground G. During this interval the trunk line leading to the selector Fis guarded by a ground potential extending from ground G through thesprings 133 and 131. side switch wiper T5 and private wiper 6S to theprivate bank contacts. Itwill be remembered that the relay St is ingizedwhen the cludedin the operating circuit of the rotary magnet '21 and,since it is aslow acting relay, it remains energized for an instantafter the rotary magnet is energized for the last time. This the relaySi is already enerside switch reaches third position. and a guardingpotential is extended from ground G in the manner described. The relay81: is quicker'than the relay S2 and thus deenergizes in time to closethe new energizing circuit for the re lay 82 before it has time todeenergize.

The calling subscriber now operates his calling device for the seconddigit 2. The second selector F operates. in response to the impulses forthis digit in the same manner as explained for the selector E, andextends connection to an idle connector H over the trunk lines 134: and135. When the connection is thus extended to the connector H its linerelay 92 becomes energized in the same manner that the selector linerelays are energized. The relay 92, upon -energizm operates to completea circuit extendmg. from ground G through springs .13? and 13S and theslow acting relay 139 128 and S2 of the selectors F and E, respectively. This circuit extends from ground G throughside switch wiper1-10, springs H1 and 142, conductor 136, private wiper 143 of theselector F, side switch wiper let-t and springs 145 and 145 to point14H. From point 1-H one branch of this circuit extends through the relay128 to battery, while another branch extends through the side switchwiper S5 (in third position) to and through the relay S2 of selector Eover a circuit which has already been traced.

The calling subscriber now operates his dial for the third digit 2,momentarily separating the impulse springs 31 and 32 in the same manneras described for the first digit. Each time the impulse springs areseparated for the third digit, the energizing circuit for the connectorline relay 92 is broken momentarily. Since the relay 139 of theconmagnet receives two impulses over this cir-.

cuit and operatesto raise the shaft wipers 86, 8? and 88 two steps. Theprivate magnet relay 119 operates in the same manner as the privatemagnet relay 83 of the selector E to close the circuit of the' privatemagnet while the vertical magnet is operating. The

circuit through the private magnet extends operation of the substationcalling device for this digit breaks the energizing circuit of the relay92 ten times. Each time the relay 92 deenergizes itcompletes a circuitextending fronrground G? through springs 137, 116, 11'4" and 148, relay119, springs 153 and 15d, rotary magnet 90 and side switch 150 (insecond position) to the battery lead 100, The rotary magnet 90 receivesten impulsesover this circuit. and operates to retate the wlpers tensteps onto the contacts of line No 2220. The private magnet relay H9 isenergized by the first impulse to the rotary magnet and again closes thecircuit of the private magnet 91. The circuit of the relay 119 is notopened long enough to permit it to deenergize until after the lastimpulse has been delivered to the rotary magnet. The relay 119 thendeinergizes and breaks the circuit of the private magnet 91 which, itthe called line is not already busy, in turn de'nergizes and permits theside switch to pass to third pos1- tion, whereby connection is completedbetween the calling and called lines. The side switch wiper 156 (inthirdfposition) extends the guarding potential from ground (al throughthe private wiper 8? to the connector private bank contacts of thecalled line. and also provides an energizing circuit for the cut ofiwinding 157 of the line switch C. The winding 15?, upon energizing,attracts the armature. 158. which operates to disconnect the linewinding 159 and ground G: from the called line, and to extend the lineconductor 160 through the springs 162 and 163 to the connector bankcontact which is engaged by wiper 86.

when the side switch wiper 150 of the connector reaches third positionthe energizing circuit is established for the ringer relay 164. Thiscircuit extends from ground Gr through the interrupter .165, relay 161C,

springs 171 and 176 and side switch wiper 150 to battery lead 100: Sincethis circuit energized only intermittently.

up his receiver.

includes interrupter 165, the relay 16% is Each time the relay 16% isenergized it operates to disconnect the calling line from the calledline and to bridge the generator M across the called line to ring thebell 115. When the called subscriber removes his receiver, or as soonthereafter as the relay 161 deenergizes, it. it happens to be energized(at the time, the called substation is provided with talking batterycurrent from the central olhce. The circuit over which this talkingcurrent flows extends from ground G to side switch wiper 156, lowerwinding of relaydfi', ringer relay springs 18S and 189, side switchwiper 1ST, shaftwiper 88, line 161, hook switch springs 186 and 185,primary winding of induction "coil 184e,

transmitter 183, impulse springs 1S2, coils 181 and 180* of thecoin-collecting device,

line 160, springs 16:2 and 163. shaft wiper- 86, ringer relay springs181 and 180, pr vate magnet springs 1T9-and 17S. upper winding of backbridge relay 1?? and side switch wiper 150 to battery lead 100. Thecurrent through the coils 181 and 180 of the coin-collecting device atthe substation A is in such direction at this time as to attract thearmature toward the coil 181*.

When the connector back bridge-relay 177 is energized by the talkingcurrent it operates to close the circuit through the relay 93. Thiscircuit extends from grolmd G through side switch, wiper 156, relay 93and springs 288 and 289 to battery lead 100. The relay 93, uponenergizing, operates to break the circuit of the ringer relay 161 at thesprings 171 and 170. and to complete a locking circuit for itselfthrough the springs 170 and 169 and side switch wiper 150. This lockingcircuit is independent of the springs 288 and 289 of the back bridgerelay 17?. Consequently, the relay 93 will not deenergize and vclose thecircuit of the ringer relay 16t again in case the called subscribershould hang. up his receiver and break the circuit of the back bridgerelay 177 before the calling subscriber has hung hen the relay 93 isen-' er ed it also operates to shift the springs 16! and 173 out ofengagement with springs 168 and 171 and into contact with springs 166and 17:2, respectively. By this operation the connections between thewindings of the relay 9:? and the trlmk conductors 134 and 135 areinterchanged. By this shifting of the connections of the relay 93 thecurrent in the'calling line is reversed This reversal of the currentcauses the polarized relay of the coin-collecting devices at substationA to attract its arma: ture in the opposite direction"that is, towardthe coil 9. When the armature is attracted in this direction it carriesthe arm 7 to the left, forcing the springs 4,

5 and 6 into engagement, as was explained in connection with Figs. 4:and 5. The engagement of these springs l, 5 and 6 shortcircuits thetransmitter 27 and shunts the 'ing the called subscriber answer, butdoes not allow him to converse through his receiver. 'hen the callingsubscriber hears the called subscriber answer he deposits a coin in thecoin chute. This coin, in pass ing down the chute, releases the arm 7from the arm 12, as has been previously explained, thereby allowing thesprings l, 5 and 6 to separate. Theseparation of these springs leavesthe talking circuit for-the calling substation in normal condition. Thenthe two subscribers may converse over the circuits represented by heavylines in Figs. 1 and 2.

After the conversation is completed, the release of the central ofliceapparatus is initiated by the hanging up of the receiver at the callingsubstation. When the receiver 25 is restored to the switch hook'26 thesprings 95" and 96. are separated, thereby breaking the energizingcircuit through the connector line relay 92. The relay 92, upondeenergizing, breaks the holding circuits of the release relays 139, 128and 82 of the switches H. F and B, respectively. Although it has notbeen previously mentioned, it will be seen that when the side switchwiper 140 of the connector passes from second to third position theholding ground of the release relays 128 and S2 of the selector switchesis transferred from ground G to ground Gr through the springs 138 and137i so that the circuits of all of the re-' lease relays are controlledby the connector line relay. When the relay 139 of the connectordeenergizes it completes a circuit from ground G through springs 13'?and 146, springs 1&7 and 191, release magnet 19:2 and ofi-norma'lsprings 193 and 194 to battery lead 100. The energization of the magnet19:2 immediately restores the mechanism of the connectorto normalposition, thereby breaking the. connection atthe called line andallowing the winding 157 of the switch C to deenergize. Thedeenergization of the release relays 128 and 8-2 of the selectors E andF closes the circuits of their respective release magnets. Theenergizing' circuit for the release magnet 78 of the selector E extendsfrom ground G through springs 110 and 112, springs 1'21 and 123. magnetTS and ofi-normal springs 50 and S1 to battery lead 100. The circuit ofthe release magnet 193 of the selector F is similar to that just tracedfor the magnet 78. The energization. of the magnets 78 and 193 restoresthe mechanism of their respective switches to normal position. When theshafts of the switches E, F and H reach their lowest positions, theenergizing circuits of their respective release magnets are broken bythe separation of the oil-normal springs. The deenergization of therelease relay 82 of the selector E also opens the holding circuit of thewinding 44 in the line switch C, whereupon its plunger returns to normalposition and all of the apparatus employed in the connection left inreadiness for another call.

The foregoing is an explanation of the manner in which connection isobtained with an idle line. It will now be explained how the callingsubscriber is given the busy signal in case the called line is alreadyin use when called by substation A. In the foregoing description it hasbeen explained how, whenever a line is busy, either by having made acall or by having been called, there is a guarding ground potential onthe connectorv private bank contacts of the said busy line. Thus if thewipers of the connector H are rotated onto the contacts of a groundpotential is extended the last impulse has been delivered to the rotarymagnet of the connector, the spring .152 engages the spring 198 beforeit breaks contact with the spring 151. The circuit of the privatemagnet91 is therefore maintained by the current extending from theprivate bank contact of the busy line through the relay 197, causing theside switch to be locked in second position and the relay 197 to beenergized. The energization of the relay 197 disconnects the rotarymagnet 90 from the impulse spring 116, and s 'fts theholding ground ofthe relay 197 and the private magnet 91 from the guarded private bankcontact to ground 6:. through the springs 196 and 198, springs 112 and141, and side switch wiper M0 in second position. In its energizedposition the relay 197 also completes a circuit over which busysignaling current flows from the busy signaling machine L to the callingsubstation. This circuit extends from the battery lead 100 through thesecondary winding of the induction coil 94?, springs 199 and 200.contact point 201. side switch wiper 1ST. ringer relaysprings 18S and189, condenser 202, thence over the heavy conductors shown in Figs. 2and 1 to and through the substation A and back the springs of the relay93.

over the other side of the line to the upper winding of the connectorline relay 92 to battery lead 100. Although the wipers of the connectorH are standing on the contacts of the called line while a. callingsubscriber is thus receiving thetbusy signal,

there is no connection between the two lines.

The connection is open on one side of the line at the private magnetsprings 17S and 179 and on the other side at the side switch wiper 187,which is locked in second position. The switches are released in thisposition by the hanging up of the receiver at the calling substation inpractically the same manner as when an idle line is called. It will benoted that when a busy line is called the current in the calling line isnot reversed. Therefore. the armature of the coin collect-ing device atsubstation A is not attracted toward the coil 9 to close the springs l.5 and 6, but remains in the position shown in Fig. 1 until at somesubsequent time an idle line is called from substation A and the call isanswered.

From the foregoing it will be seen that, the

calling subscriber's telephone set is moperative. for talking after thecalled subscriber answers. The calling subscriber can listen and hearthe response of the called subscriber, but cannot use his transmitteruntil after a coin or the lik has been deposited in the slot at thecalling substation. This is the only way in which the calling subscribercan talk to the called subscriber.

A further advantage of iny improved system is as follows: Intelephonesystems giving so-called measured service it is very oftendesired thatno charge shall be levied for calling certain lines, such aslines which terminate at the central otiiceover which operators orexchange attendants are called,

etc. In the. system shown herein it is very easy to provide for freeservice when certain lines are called. This may be done by makmg thelines which are to be called tree of charge accessible from specialconnector" switches. These special connectors may be similar in allrespects to the connector H, with the exception that the line relay 92should be connected with the trunk conductors 134 and 135 direct insteadof through In these special connectors the relay corresponding to therelay 913 would have no springs corresponding to the springs 166. 167,168. 172, 173 and 174. Since the line relay of these connectors isconnected directly to the line conductors, the current is not reversedin the calling line upon the removal of the receiver ata substationwhich has been called through one of the special connectors. Since thecurrent in the calling line is notreversed. the calling telephone is notmade inoperative for talking. and consequently the calling subscriberoperative.

memos does not need to deposit a coin before he can talk. I

What I claim as my invention is 1. In a telephone system, a calling anda called subscriber's line, means including automatic progressivelymovable switches controllable over two sides of a line in series forestablishing connection between' said lines means for rendering thecalling telephone inoperative for talking when the called subscriberanswers, and means for thereafter rendering said telephone operative.

2. In a telephone system, a calling and it called subscriber's line,means including automatic progressively movable switches controllableover two sides of a line in series for establishing connection betweentwo of said lines. means for reversing the current in the calling linewhen the called subscriber of currentto render said telephoneinoperative for talking. a mQ'asured service device, and meanscontrolled by the operation thereof for thereafter rendering saidtelephone 3. In a telephone system, a plurality of subscribers linesdivided into groups, means including automatic switches having motion ofone character to select groups and a second motion to find aline in theselected 95 group for establishing connection between two of said lines,means for controlling the two sides of a line in' series to operate saidswitches, means for rendering said calling telephone inoperative fortalking when the 9 called party answers, and means for thereafterrendering said calhng telephone op erative.

I. In a telephone system, a plurality .of

subscriberslines divided into groups, means including automatic switcheshaving motion of one character to select groups'and a. 'second motion tofind a line in the selectedgroup for establishing connection between twosides of a line in series to operate said switches. means for reversinthe current in the calling line when the called party answers, meansresponsive to said reversal of.

.two of said lines,' means for controlling the current to render thecalling telephone inop- I erative for talking. measured'service device,and means controlled by the operation of said device for rendering saidcalling telephone operative.

In a telephonesystem. a calling and a called subscribers line, meansincluding automatic switches having motion In two intersecting planesfor establishing a connection between two of said lines, means forcontrolling the operation of said switches over two sidesof a linecircuitin series, a transmitter and a receiver on each of said lines,and means controlled upon the re sponse of the called subscriber forclosing a short-circuit directly around said transmitter on the callingline, said short-circuit excluding the calling receiver.

6. In a telephone system, a calling and a called subscribers line,-means including automatic switches having motion in two intersectingplanes for establishing a connection bet-ween two of said lines, meansfor controlling the. operation of said switches over two sides of a linecircuit in series, a transmitter and areceiver on each of said lines.means controlled upon the response of the called subscriber for closinga short-circuit directly around said transmitter on the calling line.said short-circuit excluding the calling receiver, a measured servicedevice, and means whereby the operation of said device opens saidshort-circuit.

'4'. In a telephone system, a central otlice. a substation telephone, aline connecting the telephone with the central oflice. a transmitter andbattery in said line, a local receiver circuit at said telephoneinductively associated with said line. and a relay for removing thetransmitter from service and for shunting the receiver to render itpartly ineifective.

S. In a telephone system. a central oflice. a substation telephone. aline connecting the telephone withthe central oilice. a transmitter andbattery in said line. a local receiver circuit at said telephoneinductively associated with said line. and a relay for short circuitingthe transmitter to "render it inoperative and for shunting the receiverto render it partly inefl'ective.

9. In a telephone system, a central otiice. a substation telephone. aline connecting the telephone with the central office. a transmitter andbattery in said line. a local receiver circuit at said telephoneinductively associated with said line. magnet controlled means forremoving the transmitter from service and for shunting the receiver torender it partly inefl'ective. and coin controlled means for restoringthe device to full operative condition. I

10. In a telephone system. a central oflice. a substation telephone. aline connecting the telephone with thecentral oflice. a transmitter andbattery in said line. a local receiver circuit at said telephoneinductively associated with said line. magnet controlled means for shortcircuiting the transmitter to render it inoperative and for shunting thereceiver to render it partly ineffective. and coin controlled means forrestoring the device to full operative condition.

11. In a telephone system. a central ofiice, a substation telephone, aline connecting the telephone with the central ofiice. a transmitter andbattery in said line. a local receiver circuit at said telephoneinductively associated with said line, a relay for removing thetransmitter from service and for shunting the receiver to render itpartly ineitective. and subscriber controlled means for restoring thedevice to full operative condition. 7

12. In a telephone system, a central oilice, a substation telephone. aline connecting the telephone with the central o flice. a transmitterand battery in said line. a local receiver circuit at said telephoneinductively associated with said line. a relay for short circuiting thetransmitter to render it inoperative and for shunting the receiver torender it partly ineffective. and subscriber controlled means forrestoring the device to full operative condition.

13. In a telephone system. a central ofiice. a. substation telephone. aline connecting the telephone with the central ofiice. a transmit terand battery in said line. a local receiver circuit at said telephoneinductively associated with said line. a relay for removing thetransmitter from service and for shunting the receiver to render itpartly ineflective. and measured service means for restoring the deviceto full operative condition.

14. In a telephone system, a central otlice. a substation telephone. aline connecting the telephone with the central ofiice. a transmitter andbattery in said line. a local receiver circuit at said telephoneinductively associated with said line. a relay for short circuiting thetransmitter to render it inoperative and for shunting the receiver torender it partly ineffective. and measured service means for restoringthe device to full operative condition.

15. In a telephone system. a central ofiice. a substation telephone. aline connecting the telephone with the central ofiice. a transmitter andbattery in said line. a local receiver circuit at said telephone inducti'ely associated with said line. a relay for removing the transmitterfrom service and for shunting the receiver to render it partlyinefi'ective. and calling controlled means for restoring the device tofull operative condition.

16. In a telephone system. a central ofiice. a substation telephone. aline connecting the telephone with the central otlice. a transmitter andbattery in said line. a local receiver circuit at said telephoneinductively associated with said line. a relay for short circuiting thetransmitter to render it inoperative and for shunting the receiver torender it partly ineffective. and calling controlled means for restoringthe device to full operative condition.

telephone inoperative for talking when the called party answers, meansfor rendering the said telephoneoperative, a third line and a stationtherefor, means for connecting the said first and third lines via saidtrunk free of charge, and means for signaling the called stations'overtheir individual lines. 18. In a telephone system, a first line and astation therefor, a second line and a station therefor, a trunk line forconnecting the two, an. automatic progressively movable switchingapparatus for closing the connection via said trunk, means for asessinga charge on the calling subscriber by rendering the calling telephoneinoperative for talkingwhen the called party answers, means forrendering the said telephone operative, a third line and a stationtherefor, means for connecting the said first and third lines via saidtrunk free of charge. I 1

19. Ina telephone system, a first line and a station therefor, a secondline and a station therefor, a trunk line for connecting the two, meansfor assessing a charge on the calling subscriber by rendering thecalling telephone inoperative for talking when the called party answers,means for rendering the said telephone operative,- a third line and astation therefor, automatic progressively movable means for connectingthe first and third lines via said trunk free of charge.

20: In a telephone system, a first line and a station therefor, a secondline and a station therefor, a trunk line for connecting the two, meansfor assessing a charge on the calling subscriber by rendering thecalling telephone inoperative for talking when the called party answers,meansoperated by a co n or the like for rendering the said telephoneoperative, a third line and a station therefor, means for connecting thesaid first and third lines via said trunk free of charge, and means forsignaling the called station over its individual line. v 21. In a tele'hone system, a first line and a statlon there or, a second line and astation therefor, a trunk line for connecting the two, an automaticprogressively movable switchng apparatus for closing the connection 59via said trlmk, means for assessing a charge on the calling subscriberby rendering the calling telephone inoperative for talking whenthecalled party answers, means operated by a coin .or the like forrendering the said telephone inoperative, a third line and a a stationtherefor, means for connecting the said first and third lines via saidtrunk free of charge. v

22. In a telephone system, a first line and 0 a station therefor, asecond line and a station therefor, '21 trunk line for connecting thetwo, means for assessing a charge on the calling subscriber. byrendering the calling telephone inoperative for talkmg when the 5 calledparty answers, means operated by a their individual lines.

coin or the like for rendering the said telephone operative, a thirdline and a station therefor, automatic progressively movable means forconnecting the first and third lines via said trunk free of charge.

I 23. In a telephone system, a first line and a station therefor, asecond line and a station therefor, a trunk line for connecting the two,means for assessing a charge on the calling subscriber by rendering thecalling telephone inoperative for talking when the called party.answers, a measured service device forrendering the said telephoneoperative, a third line and a station therefor,

means for connecting the said first and third lines via said trunkfreeof charge, and

means for signaling the called stations over;'

their individual lines.

24. In a telephone system, a first line and a station. therefor, asecond line and a station therefor, a trunk line for connecting' thetwo, an automatic progressively. movable.

a station therefor, a second line and a sla tiontherefor, a trunklinefor connecting the two, means for assessing a charge on the callingsubscriber by rendering the calling telephone inoperative for talkingwhen the called party "answers, a -measured service device for renderingthe said't'elephone operative, a third line anda station therefor,automatic progressively movable means for connecting the first and thirdlines via said trunk free of charge- 26. In a telephone system, a firstline and a station therefor, a second line anda sta .tion therefor, atrunk line for connecting the 7 two, electrically operated means forassess-- 1 ing a charge on the calling subscriber by rendering thecalling telephone inoperative for talking when the called party answers,7 means for rendering the said telephone op-' lines via said tru free'ofcharge, and

erative, a third line and a station therefor, v means forconnectinugkthe said first and third- I means for signaling the calledstations over 2 27. In a telephone system, a first man a stationtherefor,-a. second line and-a sta tion thereforf a' trunk line forconnecting the two, an automatic progresslvely IIIIIOVabIG t e' cona,

switching apparatus .for closin nection via said trunk, electrica yoperated means for assessing a charge on the calling subscriber byrendering thecalling telephone inoperative for talking when the calledparty answers, means for rendering the said telephone operative. a thirdline and a station therefor. means for connecting the said first andthird lines via said trunk free of charge.

28. I11 a telephone system, a first line and a station therefor. asecond line and a station therefor. a trunk line for connecting the two.electrically ope ated means for assessing a charge on the callingsubscriber by rendering the calling telephone inoperative for talkingwhen the called party answers means for rendering the said telephoneoperative. a third line and a station therefor. automatic progressivelymovable means for connecting the first and third lines via said trunkfree of charge.

29. In a telephone system, a central office. a substation telephone, aline connecting the telephone with the central oflice, a transmitter andbattery in said line. a local receiver circuit at said telephoneinductively associated with said line. a relay for removing thetransmitter from service while retaining the receiver in service, andautomatic progressively movable central office switching apparatus forapplying said battery to said line.

30. I11 a telephone system, a central officc. a substation telephone. aline connecting the telephone with the central ofiice, a transmitter andbattery in said line. a local receiver circuit at said telephoneinductively associated with said line, a relay for short circuiting thetransmitter to render it inoperative while retaining the receiver inservice. and automatic progressively movable central ofiice switchingapparatus for applying said battery to said line.

31. In a telephone system, a central office. a substation telephone. aline connecting the telephone with the central ofiice, a transmitter andbattery in said line, a local receiver circuit. at said telephoneinductively associated with said line, a relay for removing thetransmitter from service and for shunting the receiver to render itpartly ineffective. and automatic progressively movable central otficeswitching apparatus for applyingsaid battery to said line.

32. In a telephone system, a central office, a substation telephone, aline connecting thetelephone with the central oflice, atransmitter andbattery in said line, a local receiver circuit at said telephoneinductively associated with said line, a relay for short circuiting thetransmitter to render it inoperative and for shunting the receiver torender it partly ineffective, and automatic progressively movablecefitral office switching apparatus for applying said battery to saidline.

gressively 33. In a telephone system, a central office, a substationtelephone, a line connecting the telephone with the central oflice, atransmitter and battery in said line, a local receiver circuit at saidtelephone inductively associated with said line, a relay for removingthe transmitter from service while retaining the receiver in service,subscriber controlled means for restoring the device to full operativecondition, and automatic progressively movable central ofiice switchingapparatus for applying said battery to said line.

34. In a telephone system, a central office, a substation telephone, aline connect ing the telephone with the central oflice, a transmitterand battery in said line, a local receiver circuit atsaid telephoneinductively associated withsaid line, a relay for short circuiting thetransmitter to render it inoperative while retaining the receiver inservice. subscriber controlled means for restoring the device to fulloperative condition. and automatic progressively movable central ofliceswitching apparatus for applying said battery to said line.

In a telephone system, a central office. a substation telephone. a lineconnecting the telephone with the central office, a transmitter andbattery in said line. a local receiver circuit at said telephoneinductively associated with said line, a relay for removing thetransmitter from service and for shunting the receiver to render itpartly ineffective subscriber controlled means for restoring the deviceto full operative condition and automatic progressively movable centraloflice switching apparatus for applying said battery to said line.

36. In a telephone system, a central office. a substation telephone, aline connecting the telephone with the central otfice, a

, transmitter and battery in said line, a local receiver circuit at saidtelephone inductively associated with said line, a relay. for shortcircuiting the transmitter to render it inoperative and for shunting thereceiver to render it partly effective, subscriber controlled means forrestoring the device to full operativecondition, and automaticpromovable central otfice switching apparatus for applying said batteryto said line.

37. In a telephone system, a central ofiice, a. substation telephone, aline connecting the telephone with the central oflice, a transmitter andbattery in said line, a local receiver circuit at said telephoneinductively associated with said line, a relay for removing the,transmitter fromservice while retaining the receiver in service,measured service means for restoring the device to full operativecondition, and automatic progressively movable central oflice switchinga pa ratus for applying said battery to said 'ne. 38. In a telephonesystem, a central oflice,

a substation telephone, a line connecting the telephone with the centraloflice, a transmitter and battery in said line, a local re ceivercircuit at said telephone inductively associated with said line, a relayfor short circuiting the transmitter to render it inoperative whileretaining the receiver in service, measured service means for restoringthe device to operative condition, and automatic progressivelymovable'central office switching apparatus for applying said battery tosaid line. 4

39. In a telephonesystem, a central oflice, a substation telephone, aline connecting the telephone with the central oflice, a transmitter andbattery in said line, a local receiver circuit at said telephoneinductively associated with said line,a relay for removing thetransmitter from service and for shunting the receiver to render itpartly' inefi'ective, and measured service means for restoring thedevice to full operative condition, and automatic progressively movablecentral office switching apparatus for applying said battery to saidline.

40. In a telephone system, a central ofice, a substation telephone, aline connecting the telephone with the central oflice, a transmit-- terand battery in said line, a local receiver circuit at said telephoneinductively associated with said line, a relay for short circuiting thetransmitter torender it inoperative and for shunting the receiver torender it partly ineffective, measured service means for restoring thedevice to full operative condition, and automatic progressively movablecentral oflice switching apparatus for applying said battery to saldline.

41. In a telephone system, a central ofice, a substation telephone, aline coectlng the telephone with the central ofice, a t

mitter and battery in said line, a local re.-

ceiver circuit at said telephone inductively associated with said line,a relay for removing the transmitter from service while retaining thereceiver 1n service,

trolled means for restoring the device to full operative condition, andautomatic progressively movable central oflice switching iiiplparatusfor applying said battery to said 42 In telephone system, a centraloiiice, a substation telephone, a line connecting the telephone with thecentral oflice, a transinita substation telephone, a line connecting thetelephonewith the central oflice, a transmitte;-- and battery in saidline, a local receiver circuit at said telephone inductively associatedwith said line, a relay for removing the transmitter from service andfor shunting the receiver to render it partly ineffective, callingcontrolled means for restoring the device to full operative condition, I

and automatic progressively movable central oflice switching apparatusfor applyingsaid battery to said line.

44. In a telephone system, a central office, a substation telephone, aline connecting the telephone with the central ofiice, a transmitter andbattery in said line, a local receiver circuit at said telephoneinductively associated with said line, a relay for short circuiting thetransmitter to render it inoperative and for shunting the receiver torender it partly ineffectivefcalling controlled means for restoringthe'device to 'full operative condition, and automatic progressivelymovable central oflice switching apparatus for applying said battery tosaid line. i n

Signed by me at Chicagofcooklcounty,

Illinois, this 15 day of July, 1910.-

Witnesses:

. A.RTHUB J. RAY,

EDWARD J. Fame.

